The invention relates to a nozzle to eject pressurized spray for use in a multitude of applications, including pharmaceutical applications involving inhalers.
The present invention has a wide range of applications in which it can be used. Reference to inhalers is merely an example of one such use.
The problem associated with metered dose inhalers (MDI) of the type using a pressurized canister of aerosol is well documented in the literature and comprises maintaining small particles of medication in a low velocity mist. The prior art has attempted to solve this problem in two ways. One way modifies the MDI to include a depressurization chamber (spacer) and the other way reduces energy in the spray by a creation of vortices in the spray flow.
Laube et al, U.S. Pat. No. 5,320,094, discloses a method of delivering a protein, in particular insulin, to the lungs. The method is characterized in that an aerosolized mist of small particles is produced in an associated medicament delivery chamber, the distance from the chamber to the patient""s mouth is set to slow the speed of aerosol particles entering the mouth and the flow rate through the chamber is regulated to a low rate of less than about 30 liters per minute.
Tritle, U.S. Pat. No. 5,203,323 discloses an expansion chamber used in combination with a MDI to intercept the high-velocity discharge of medicament from a pressurized inhaler. The expansion chamber has a constant volume with no moving parts or external vents for ease of cleaning, for durability, and for optimizing the mist concentration. The dimensional parameters of the chamber are optimized to produce a maximum concentration of medicament mist while neutralizing the high velocity of the inhaler discharge. The chamber is provided at one end with an inlet aperture into which the inhaler mouthpiece sealingly fits. At the chamber other end is provided an outlet aperture with a chamber mouthpiece over which a user""s mouth is closed. The chamber mouthpiece aperture is sized so that substantially all of the medicament mist is uniformly withdrawn during a single short breath by a user suffering from a respiratory ailment such as asthma. One end of the chamber is a removable cap to facilitate cleaning. Also to facilitate cleaning, a brush is provided that is formed to the shape of the chamber internal dimensions. Used in combination with the chamber with the cap removed, the chamber is cleaned by the brush, typically with soap and water, and the chamber can be reused indefinitely at very nominal cost. To maintain cleanliness during nonuse, protective cover caps are provided to close the inlet and outlet apertures. Larson et al., U.S. Pat. No. 5,040,527 discloses an apparatus for dispensing a measured amount of a spray-entrapped product, typically dispensed by a metered dose inhaler device, includes an elongated passageway having a mouthpiece portion and a main chamber portion. The metered dose inhaler is mounted between the mouthpiece and main chamber portions such that upon operation its spray is directed away from the mouthpiece. A two-position valve is provided to allow a first, low-level flow to be developed through the unit, followed by a higher flow rate as the metered dose inhaler unit is operated. This increased flow, passing through the device in the direction opposite to that of the MDI spray, contacts the spray plume to cause a high level of mixing and a decrease in spray particle size which results in a draw of the spray medication into the lungs of the user.
Zoitan et al., U.S. Pat. No. 4,926,852 discloses an apparatus for use in inhaling pharmaceutical aerosols. The apparatus includes a mouthpiece and a rigid housing for receiving an aerosolized medicine. The rigid housing has one or more orifices which are spaced from the mouth piece so that flow through the housing is possible but is limited by the orifice(s) to a desired volumetric flow rate.
Hughes, U.S. Pat. No. 4,241,877 discloses a vortex generating device wherein a flow passage aligned with a flow axis is connected between a fluid inlet and a fluid outlet, and a plurality of tornado-like gas vortices are generated in the flow passage in an annular arrangement around the flow axis; the vortices also rotate about the flow axis. The combination of shock wave formation and vortex generation in a gas stream permits atomization of liquids.
Sperry, U.S. Pat. No. 4,852,561 discloses an MDI with aerosol chamber dispersion techniques to reduce such ailments as thrush and a one-way valve that allows the user to draw the drug from the aerosol chamber and exhale into the MDI without disturbing its contents or contaminating the MDI with exhaled organisms. The aerosol cartridge is located inside the aerosol chamber and is activated by a unique valve that directs the discharged contents into the aerosol chamber for aerosolization. The aerosol chamber is shaped to optimize the aerosolization process while maintaining a good shape to hold and carry about in a jacket pocket or purse.
Larson et al., U.S. Pat. No. 4,598,836 discloses a spray-entrapped product such as dispensed by an MDI device includes an elongated passageway having a mouth-piece portion and a main chamber portion. The MDI device is mounted to direct a medication spray into the main chamber. A first air inlet allows a low-level inspiratory breath to be developed through the unit prior to operation of the MDI device. When the MDI device is operated a second, air inlet is opened, allowing a higher-level breath to be developed, which causes a high level or mixing with the MDI spray for efficient draws into the lungs. The second air inlet remains open after MDI operation ceases, insuring that a complete, high flow rate breath can be made to fully sweep the medication out of the chamber.
Wong, U.S. Pat. No. 4,972,830, discloses a device for dispersing a fluid supplied from an external source having a feed supply. An inlet accepts a fluid from the feed supply for passing the fluid through an outer perimeter of the device in a downstream direction and has an axis contained in a plane. An outlet is provided downstream from the inlet for allowing the fluid to exit. A bluff body is positioned between the inlet and the outlet and has an axis contained in a plane perpendicular to the inlet axis plane. At least one passageway internal to the outer perimeter and external and extending downstream from the outlet for passing a second fluid is provided.
The prior art references described above show a variety of structures for achieving the objective of maintaining particles in a low velocity spray, including swirls, chamber shapes and vortex development. Many of the prior art devices typically retain a significant portion of the drug entering the device. This will adversely affect the uniformity of the emitted doses and decrease the absolute quantity of drug reaching the patient. This is especially characteristic of spacer devices but is also associated with the Wong device, described above. Therefore, there is still a need for a nozzle which has simple construction, small size, reliability and good atomization while generating discrete particle sizes. It is also desirable that the nozzle work well with liquids, solutions or suspensions for versatility.
While the types of vortices as aforenoted have particular advantages, they also have attendant disadvantages some of which have been mentioned.
It is therefore a principal object of the invention to overcome the shortcomings of the nozzles heretofore mentioned.
It is a further object of the invention to provide a nozzle of use in MDIs to deliver liquids, solutions and suspensions.
It is a further object of the invention to provide a nozzle which has simple construction, small size, reliability and good atomization.
It is a further object of the invention to provide a nozzle which has simple construction, small size, reliability, good atomization uniform particle size, low drug retention and more reproducible drug delivery over prior art devices.
The invention comprises a vortex nozzle to eject the pressurized spray. The nozzle comprises an inlet portion with an outlet which is tangential to the inlet of a swirl chamber through which the substance is sprayed. The design of the present invention is simpler and less costly to manufacture in comparison to the prior art nozzles. In a particular example, that will be detailed herein, the nozzle is utilized in an inhaler for aerosolized medication which may be an MDI or other type.
While the present invention has obvious utility in the delivery of aerosolized medicines to the pulmonary system of mammals and to other body parts, it should be evident that it has industrial use as well in the delivery of paints, cosmetics, hair sprays, insect repellants, lock de-icers and other anti-freezing compositions, and the like.